Rinse Water Regeneration in Stainless Steel Pickling

Various issues related to the rinse water regeneration in stainless steel pickling were discussed. The tests were carried out mainly in one of Outokumpu's production plants in Sweden. It was observed that the membrane technique was used for rinse water treatment. A filtering system based on reverse osmosis was developed to separate the acids and metals from the rinsing water. A pre-filtering method necessary for reverse osmosis was tested. For the recovery of the mixed acids, the concentrate of reverse osmosis was further treated with electro dialysis. It was found that the proposed rinse water recycling concept reduces the overall usage of water.